Cameras with mechanically ignited flashcubes

ABSTRACT

A camera which mechanically ignites lamps of flashcubes. An ignition plunger of the camera is supported for movement from a rest position to an igniting position, and a transmission from the shutter-release structure acts on the plunger to displace the latter from its rest position toward its ignition position. This transmission has a non-linear characteristic according to which it will displace the ignition plunger from its rest position rapidly toward its ignition position during an initial part of the movement of the shutter release means while during a final part of this movement the transmission rate is slower so that the plunger is displaced almost to its ignition position during the initial part of the movement of the shutter-release structure.

United States Patent Lange 1541 CAMERAS WITH MECHANICALLY IGNITED FLASHCUBES [72] Inventor: Karl-Heinz Lange, Bunde, Germany [73] Assignee: Balda-Werke, Bunde (Westf), Germany [22] Filed: April 28,1971

[21] Appl.No.: 138,026

[30] Foreign Application Priority Data [56] References Cited UNITED STATES PATENTS 3,584,555 6/1971 Bresson ..95/ll.5R

[451 Aug. 1,1972

Primary Examiner-Samuel S. Matthews Assistant Examiner-Robert P. Greiner Attorney-Blum, Moscovitz, Friedman & Kaplan 5 7] ABSTRACT A camera which mechanically ignites lamps of flashcubes. An ignition plunger of the camera is supported for movement from a rest position to an igniting position, and a transmission from the shutter-release structure acts on the plunger to displace the latter from its rest position toward its ignition position. This transmission has a non-linear characteristic according to which it will displace the ignition plunger from its rest position rapidly toward its ignition position during an initial part of the movement of the shutter release means while during a final part of this movement the transmission rate is slower so that the plunger is displaced almost to its ignition position during the initial part of the movement of the shutter-release structure.

10 Claims, 3 Drawing Figures PATENTEDAUG 1 I972 I 3,680,454 skin 1 nr 3 IN NTOR. KARL HE! LANGE A 'lTORNFIYS PATENTED H973 3,680,454 sum 2 OF 3- INVENTOR. KARL HEINZ LAN GE ATTORNEYS PATENTEDMIB nan 3,680,454

' sum 3 or 3 INVENTOR] KARL HElNZ LANGE BACKGROUND OF THE INVENTION The present invention relates to cameras.

In particular, the present invention relates to cameras which are adapted to use flashcubes in order to provide flash illumination.

Such cameras conventionally advance an unignited flash lamp of the flashcube into an exposure position simultaneously with the film transport operation. Thus, the flashcube has a plurality of flash lamps which are successively displaced to the exposure position where they are successively ignited as the successive film frames are moved to the exposure position. Cameras of this general type are known as disclosed for example in the German Auslegeschrifts 1,267,969 and 1,279,452.

In recent times flashcubes have been provided wherein the lamps are not electrically ignited but instead are mechanically ignited. Such lamps are conventionally provided each with a relay spring or ignition spring which produces ignition by being struck against a chemical detonating composition in response to a force comingfrom the camera itself, so that in this way detonation and ignition of each lamp are produced. In order to avoid accidental ignition of such flash lamps, it is only possible to have access to the relay or ignition spring through a relatively deep opening. This arrangement which is necessary for safety purposes has created problems in the provision of structure which will effectively coact with such flash lamps.

SUMMARY OF THE INVENTION It is accordingly a primary object of the present invention to provide a construction which will effectively and safely bring about ignition of mechanically ignitable flash lamps of the above type.

A further object of the present invention is to provide a structure which can readily change existing camera structures for use with mechanically ignitable flash lamps of the flashcubes.

A further object of the present invention is to provide a structure which will bring about a rapid move ment of a lamp-igniting plunger almost up to its ignition position during an initial part of the movement of the shutter-release structure while utilizing the remainder and greater part of the movement of the shutter-release structure to achieve a force sufficient to bring about a final movement of the plunger to produce ignition in synchronism with the tripping of the shutter.

It is also an object of the present invention to prevent tripping of the shutter when a flash lamp which is in the exposure position has already been ignited.

Furthermore, it is an object of the present invention to provide a camera which will effectively trip the shutter when a flashcube is not used.

In addition it is an object of the invention to provide structure capable of accomplishing the above objects while at the same time being relatively simple and inexpensive.

In accordance with the invention the camera includes an ignition plunger guided for movement from a rest position toward an ignition position. A shutterrelease means is provided for tripping the shutter, and a non-linear transmission means transmits movement of the shutter-release means to the plunger to displace the latter from the rest position to the ignition position thereof. This non-linear transmission means brings about a rapid movement of the plunger toward its ignition position during an initial part of the movement of the shutter-release means while during a final part of the movement thereof the transmission ratio is such that the plunger can be moved only at a slow rate or at the same rate as the shutter-release structure.

BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. I is a fragmentary sectional elevation illustrating one embodiment of a structure according to the invention;

FIG. 2 is a fragmentary partly sectional elevation taken at right angles to the plane of FIG. 1 and illustrating further details; and

FIG. 3 is a fragmentary sectional elevation showing another embodiment of the structure of FIG. 1.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring first to FIGS. 1 and 2, a camera housing 1 is fragrnentarily illustrated therein in section. The structure of the camera housing serves to support for rotary movement a flashcube socket 2. The flashcube socket 2 has four operating positions, and in correspondence with these four operating positions the flashcube socket 2 is formed with four openings 3 of which one is visible in FIG. 1, these openings being spaced from each other by about the axis of rotation of the socket 2 so that the openings 3 will successively move into the position shown in FIG. 1 during successive exposures. In each operating position of the flashcube there will be one of these openings 3 situated in registry with an opening 4 in the top wall of the camera housing By reason of the registry of the successive openings 3 with the opening 4 it is possible in each operating position of the socket 2 and the flashcube carried thereby for an ignition plunger 5 to move upwardly through the registering openings 3 and 4 into the relatively deep opening of the flashcube so as to have access to the mechanical ignition structure therein. The ignition plunger 5 is in the form of an elongated body guided for longitudinal movement in an opening 10 which is formed in an interior horizontal wall of the housing and in an elongated vertically extending groove 11 which is also formed in the interior of the housing. The ignition plunger 5 is shown in solid lines in FIG. 1 in its lower rest position where the top end surface 6 of the plunger 5 is situated beneath the rotary socket 2. Thus in the rest position of the plunger 5 it is possible for the socket 2 to turn from one position to the next. The plunger 5 is movable upwardly from its rest position toward an ignition position. However, before reaching its ignition position the end surface 6 will first reach the elevation 7 schematically indicated in FIG. 1. At this elevation the plunger 5 has moved almost up to the ignition position. When the end surface 6 is at the elevation 7 the plunger 5 is situated directly below the ignition spring 8 of the mechanically ignitable flashcube the details of which are not further illustrated. When the plunger 5 has reached the ignition position 9 which is schematically indicated as being the highest position of the plunger 5, the ignition of the flashcube takes place. The flashcube 5 has a lower elongated portion in the form of a rack 12.

Through this rack 12 of the ignition plunger 5 a nonlinear transmission means acts on the ignition plunger 5 in accordance with the invention, and this transmission means includes a rotary gear sector 14 having teeth 13 which mesh with the rack 12. The gear sector 14 is supported for rotary movement on a horizontal shaft 17 which is carried by the camera housing, and the gear sector 14 is fixed to one end of a sleeve 15 through which the shaft 17 passes. This sleeve 15 is also fixed to an arm 16 so'that components 14-16 form a single unit which is turnable on the shaft 17. This unit forms an output member of a lost-motion mechanism of the nonlinear transmission means.

The arm 16 extends from a hub which is fixed to the end of sleeve 15 opposite from the sector 14, and this hub is-formed with an arcuate cutout 59 in which a tooth 18 of the lost-motion structure is located. This tooth 18 is fixed integrally to and extends axially from a rotary input member 19 of the lost-motion transmission structure, and the cutout 59 limits the extent of free movement of the tooth 18 and thus the extent of free movement of the input member 19 with respect to the output member 14-16. The input member 19 is also supported for rotary movement by the shaft 17. A transmission spring 20 is coiled about member 19 and has an end engaging arm 16 to maintain the latter in engagement with the tooth 18 except when the transmission spring 20 yields during operation of the lost-motion.

The input member 19 has a flange portion 21 extending radially from the shaft 17 and behind which the other end of the spring 20 is located. This flange portion 21 is formed with an elongated cam groove or notch 22 having the configuration most clearly apparent from FIG. 1. Thus in the region of the shaft 17 the cam notch 22 extends substantially radially with respect to the shaft 17 while distant from the latter the inclination of the notch 22 changes so that in this way the non-linearity of the transmission means is achieved.

The input member 19 of the lost-motion transmission is freely tumable on the shaft 17 which also supports the output member 14-16 for free rotary movement. The cam notch 22 receives a cam pin 23 which serves to transmit motion to the non-linear transmission means from a shutter-release means.

The manually operable shutter-release means of the illustrated camera includes a lug 24 of a vertically movable shutter-release plate 25, the pin 23 being fixed to the lug 24 as by being riveted thereto, for example. The vertically movable shutter-release plate 25 is guided in the camera housing in an unillustrated manner for longitudinal vertical movement. This plate 25 has also a lug 26 engaged by a manually operable plunger 27 the top end of which is accessible to the operator so that when the operator presses down on the plunger 27, as indicated by the arrow at the upper left FIG. 1, the plate 25 will be moved downwardly in order to initiate the shutter-release operations. An unillustrated spring holds the components 25 and 27 in an upper rest position. A rivet or pin 28 serves to connect to the plate 25 a swingable shutter-tripping member 29 in the form of a lever which is tumable about the pin 28. This shutter-tripping member 29 has a number of different functions which are described in detail in the above-mentioned German Auslegeschrift 1,267,969. For the purpose of the present invention, however, it is only necessary to refer to the following details of shutter-tripping member 29:

The lever 29 has at its lower end a portion 30 which is urged by a spring 31 against a stop 32 in the form of a lug extending from the plate 25. At its top end the lever 29 has a lug 33 which extends perpendicularly with respect to the plane of FIG. 2 and which coacts successively with four projections 34 of the rotary flashcube socket. At its upper right portion the shutter-tripping member 29 is provided with a curved lug 35 which is perpendicular to the plane of FIG. 2 and which has a downwardly directed convex surface, as viewed in FIG. 2. During the operations which are described below the lever 29 is swung in a counterclockwise direction, as viewed in FIG. 2, from the position shown in FIG. 2 to a position where the lug 35 is situated over a stationary cam 36 suitably mounted in the camera and having an upwardly directed convex surface engaged by the lower convex surface of lug 35 during downward movement of the plate 25 so as to cam the lever 29 in opposition to the spring 31 in a counterclockwise direction, as viewed in FIG. 2. A stationary plate 37 of the camera has a lug which forms the cam 36. In order to determine the position to which the lever 29 is swung by a projection 34 of the socket 2, the camera has a stationary stop 38 which engages the upper left edge portion 39 of the lever 29, as viewed in FIG. 2. In response to actuation of the unillustrated film transport structure of the camera the socket 2 is turned in a direction which will move the projection 34 shown in FIG. 2 engaging the lug 33 to the left, as viewed in FIG. 2, so that in opposition to the spring 31 the lever 29 will initially be swung in a counterclockwise direction about the pin 28 as viewed in FIG. 2 until the edge 39 engages the stop 38. When the edge 39 of lever 29 engages the stop 38 the next opening 3 has moved into registry with the opening 4. In this position the flashcube has been turned through so that the next unexposed lamp has reached the exposure position. The lever 29 also has at the region of the pin 28 a projection 40 which coacts with the arm 16 of the output member in a manner referred to below.

The vertically movable plate 25 of the shutterrelease means has an upper extension 41 provided at its top end with a lug 42 which extends perpendicularly with respect to the plane of FIG. 2 and to the right from the plane of the extension 41, as viewed in FIG. 1. This lug 42 is adapted to engage under certain, operating conditions referred to below a stop lever 43 which is also supported for free rotary movement by the shaft 17. This lever 43 forms a stop means coacting with the lug 42 in order to prevent actuation of the shutter when the plunger 5 encounters an already ignited flash lamp, as explained below. This stop lever 43 has at the region of the shaft 17 a projection 44 urged by a spring 45 into engagement with a stop tooth 46 which is fixed to and projects axially from the gear sector 14. The spring 45 is coiled about the shaft 17 between the sector 14 and the lever 43. One end of the spring 45 engages the tooth 46 at its right side as viewed in FIG. 1, while the other end of the spring 45 engages behind a lug 47 projecting from the upper edge of the lever 43 perpendicularly to the plane of FIG. I. The stop means which includes the lever 43 also includes a projection 48 in the form of a lug extending from the top edge of the lever 43 in a direction opposite to the lug 47. This lug 48 is adapted to coact with a stop lug 49 of a sensing means formed by a lever 50 for the purpose of preventing the stop means 43 from interfering with the operation of the shutter in the case where there is no flashcube in the camera so that daylight exposures are made.

The sensing means 50 thus is in the form of a lever supported for free swinging movement on a stationary pin 51 carried by the camera housing in the interior thereof. A spring 52 acts on the arm 53 of the lever 50 to urge the arm 53 upwardly into engagement with a sensing pin 54 of the sensing means. This pin 54 will sense the presence or absence of a flashcube. The pin 54 is engaged directly by part of the flashcube which is inserted into the socket 2. When there is no flashcube in the socket the sensing pin 54 of the sensing means is in its upper solid line position shown in FIG. I where the spring 52 turns the sensing lever 50 so as to locate the lug 49 in its lower solid line position shown in FIG. 1, and in this position the lug 49 is in the path of movement of the lug 48 so that the stop means 43 cannot interfere with the operation of the shutter-release means during daylight exposure. However, when a flashcube is inserted into the socket 2 the flashcube will depress the pin 54 so as to swing the lever 50 in opposition to the spring 52 into the dot-dash line position shown in FIG. 1 where the lug 49 is beyond the path of movement of the lug 48, so that now it is possible under conditions referred to below for the stop means 43 to coact with the lug 42 of the shutter-release means.

In the second embodiment of the invention which is illustrated in FIG. 3, for purposes of economy and simplicity, the entire stop means 43 and the parts associated therewith are omitted. Also it will be noted that the arm 16 is omitted and instead the spring engages a relatively short projection of the gear sector 14. Instead of the stop means 43 the embodiment of FIG. 3 is provided with a releasable pawl means 60 in the form of a bell crank swingable on the shaft 17 and having pawl tooth 62 at its top end, as viewed in FIG. 3. This tooth 62 is located over a tooth 63 which projects from the plunger 5. A spring at of the releasable pawl means urges the pawl 60 to turn in a clockwise direction about the shaft 17, as viewed in FIG. 3. This releasable pawl means 60 includes a release arm 64 extending horizontally from the shaft 17, as viewed in FIG. 3, and adapted to be acted upon by the projection 40 of the shutter-tripping member 29 in a manner referred to below. Thus, in the embodiment of FIGS. 1 and 2 the projection 40 coacts with the arm 16 whereas in the embodiment of FIG. 3 the projection 40 coacts with the pawl-release arm 64. It will be noted that not only has the stop means 43 been eliminated from the embodiment of FIG. 3 but also the sensing means 49-54 is eliminated.

The structure described above and shown in the drawings operates as follows:

After one exposure has been completed the operator will actuate the unillustrated film transport of the camera so that the socket 2 will turn and a projection 34 thereof will rotate through an angle sufficient to locate the edge 39 of lever 29 in engagement with the stop 38. During this turning of the shutter-tripping member 29 the spring 31 is partially tensioned. It will be noted that the spring 31 is coiled about the pin 28 and has one end extending into a notch of a lug of the plate 25 while the opposite end of the spring 31 engages a part of the lever 29 to urge the latter in a clockwise direction, as viewed in FIG. 2. Thus, this movement of the edge 39 into engagement with the stop 28 will take place in opposition to the spring 31 so as to store in the latter part of the energy which is stored therein just prior to opening of the shutter. In this way the turning of the socket 2 is used for storing in the spring 31 part of the energy required for opening the shutter. As was pointed out above, this turning of the socket 2 locates the next opening 3 thereof in re gistry with the opening 4 of the camera housing, so that the ignition plunger 5 can move through these aligned openings 3 and 4 in order to ignite the flash lamp. Thus, with a flashcube in the socket 2, the camera is placed in this way in readiness to make an exposure.

Upon actuation of the shutter-release means by the operator, who manually depresses the plunger 27 downwardly as indicated by the arrow at the upper left of FIG. I, the shutter-tripping member 29 moves downwardly with the plate 25 because it is connected thereto by way of the rivet or pin 28. At the same time, the tooth 23 of the non-linear transmission means moves downwardly with the lug 24 of the plate 25, and through the cam notch 22 of the transmission means the input member 19 of the lost-motion mechanism is turned. The configuration and angular position of the cam notch 22 is such that initially, which is to say during the initial part of the operation of the shutterrelease means, a relatively small extent of movement of the shutter-release means will result in a rotary movement of the input member I9 which is as large as possible.

During this initial part of the operation of the nonlinear transmission means in response to operation of the shutter-release means, the transmission spring 20 maintains the arm 16 in engagement with the tooth 18 projecting from the input member 19 so that the lostmotion mechanism has not yet started to operate and instead the output member 14-16 rotates together with the input member I9. At this time the teeth 13 of the output member coact with the rack 12 of the ignition plunger 5 so that the ignition plunger at the very beginning of the operation of the shutter-release means moves very rapidly to reach the elevation 7 indicated in FIG. I.

Simultaneously with the rotary movement of the output member 14-16 the tooth 46 fixed to the sector 14 turns and thus results in counterclockwise swinging of the stop lever 43. The spring 45 maintains the projection 44 of the lever 43 in engagement with the tooth 46 which is fixed to and projects from the sector 14. Thus, at this time, which is to say during the initial part of the operation of the shutter-release means, the stop lever 43 will turn approximately and reaches a substantially vertical attitude where the top end of the lever 43 still has not turned into the path of downward movement of the lug 42 of the shutter-release plate 25. Of course, the lug 42 moves downwardly with the plate 25 due to the connection of lug 42 to the plate 25 through the extension 41 of the latter.

Assuming that an unignited flash lamp is situated in the exposure position, then the top surface 6 of the ignition plunger will engage the ignition spring 8 which acts as a stopterminating the continued upward movement of the plunger 5 to the ignition position. Thus, during the continued downward movement of the shutter-release means by the operator the tooth 18 will move away from the arm 16 along the cutout 59 and the spring 20 yields at this time so that the input member 19 turns with respect to the output member 14-16 and the lost-motion mechanism operates. With this first embodiment of the invention the force of the spring 20 is such that it is incapable of acting through the output member 14-16 on the plunger to overcome the resistance of the ignition spring 8 so that the ignition of the flash lamp cannot be brought about solely through the force of the spring 20. However, the spring is strong enough to displace the ignition plunger 5 all the way up to the ignition spring 8 to a location just short of actual ignition of the lamp. Therefore, since the resistance of the spring 8 serves to prevent further upward movement of the plunger 5, during the continued downward movement of the shutter-release means the plunger 5 no longer moves and the stop lever 43 remains in its substantially vertical position where it is situated beyond the path of downward movement of the lug 42 so that the stop means 43 at this time does not interfere with the operation of the shutter.

Because the advance of the film has resulted in tuming of the socket 2 in order to place the edge 39 of lever 29 in engagement with the stop 38, the lug 35 is located over the stationary camming lug 36, and therefore during the continued downward movement of the shutterrelease means this cam 36 acts on the lug 35 to continue to turn the lever 29 in a counterclockwise direction in opposition to the spring 31 as the lever 29 moves downwardly beyond the stop 38. Thus, additional force is stored in the spring 31 during the time when the operator moves the shutter-release means downwardly.

At the instant when the upper right edge of the lug 35 moves downwardly beyond the lower left edge of the cam 36, as viewed in FIG. 2, the spring 31 sharply swings the lever 29 in a clockwise direction, as viewed in FIG. 2, in order to bring about tripping of the shutter. Thus, the shutter-tripping member 29 is now driven by the spring 31 back to the position of FIG. 2 and the lower projection 30 of the lever 29 again engages the stop lug 32 of the plate 25. During its return into engagement with the lug 32 the projection 30 of the shutter-tripping member 29 has engaged an unillustrated shutter sector and has propelled it so as to open the shutter. At the same time the projection 40 of the shutter-tripping member 29 has either shortly before or at the beginning of the opening of the shutter struck downwardly against the arm 16 which in the meantime has been turned through approximately 90 in a counterclockwise direction from the position of FIG. 1, so that the added force required to displace the plunger 5 upwardly in opposition to the ignition spring 8 is provided in this way, and the output member 14-16 is thus acted upon by the shutter-tripping member 29 itself in order to bring about the final increment of movement of the ignition plunger 5 in order to act on the ignition spring 8 to ignite the flash lamp. In this way the force derived from the shutter-tripping member 29 supple ments the force of the spring 20. The total of the force of the spring 20 and the force from the spring 31 delivered through the projection 40 of lever 29 is sufficient to achieve the additional turning of the output member 14-16 required to actuate the ignition spring 8 so as to cause the flash lamp to be ignited. In this way the ignition of the flash lamp takes place in synchronism with the opening of the shutter.

After the tripping lever 29 has returned to its rundown position, the projection 40 thereof has turned beyond the arm 16, so that when the operator releases the plunger 27 the unillustrated return spring returns the plate 25 to its rest position and through the pin-andslot transmission 23, 22 the input member 19, the spring 20, and the tooth 18 of the lost-motion mechanism serve to return all of the components to their rest position, the tooth 46 also acting on the projection 44 to return the stop lever 43 to its rest position shown in solid lines in FIG. 1. Thus the teeth 13 of the sector 14 acts at this time on the plunger 5 to return the latter downwardly to its rest position beneath the socket 2 so that the latter can again turn in order to bring about the setting up of the parts for the next exposure.

Assuming that an attempt is made to provide for exposure with a flashcube in the socket but with a lamp which has already been ignited, then the plunger 5 during its upward movement will not encounter at its top surface 6 any resistance from the ignition spring 8, since this spring has already been impelled to one side, and thus under these conditions the plunger 5 will move all the way up to its ignition position only with the force of the spring 20. Thus, under these conditions the output member 14-16 will turn through a somewhat greater angle then under the above-described conditions, causing not only the plunger 5 to move all the way up to its ignition position, without igniting the already lignited lamp, but also causing the stop means 43 to swing further so that the top end thereof is now located beneath and in the path of downward movement of the lug 42 of the extension 41 of the plate 25. In this way the stop means 43 will prevent movement of the shutter-release means all the way to the shutterrelease position, and the operator will feel the re sistance to the downward movement of the shutter release means so that in this way an indication is given.

to the operator that it is necessary to change the flashcube. Thus, the stop means 43 acts as a fully reliable safety device for preventing an attempt to make exposures with already ignited flash lamps.

In the event that it is desired to make daylight exposures, there will be no flashcube in the socket 2, so that the sensing pin 54 and the arm 53 of the sensing lever 50 of the sensing means will be raised by the spring 52 to the solid-line position shown in FIG. 1 where the lug 49 of the lever 50 is in the path of movement of the lug 48 of the stop lever-43. Therefore, at this time the lug 49 will coact with the lug 48 to prevent the lever 43 from interfering with the operation of the shutterrelease means, and daylight exposures can take place through this expedient.

With the second embodiment of the invention which is illustrated in FIG. 3, the advantage of automatic prevention of shutter-release with an already ignited flash lamp has been dropped, but at the same time there is the advantage of requiring a substantially lesser force to be delivered to the plunger from the shuttertripping member 29 or from a part of the shutter. In accordance with the invention in this embodiment of the invention the spring is strong enough to displace the plunger 5 all the way to the ignition position without requiring any additional force such as that delivered through the projection 40 of the lever 29 from the spring 31. However, in order to prevent the ignition of the lamp immediately upon depression of the plunger 27, the releasable pawl means 60 is provided. As the plunger 5 of FIG. 3 moves upwardly toward its ignition position the tooth 63 of the releasable pawl means engages the tooth 62, so that in this way the releasable pawl means functions to prevent the plunger 5 from being moved by the spring 20 all the way to the ignition position. Thus, the tooth 63 coacts with the tooth 62 in order to hold the plunger 5 at the elevation 7 just short of the ignition position. With this embodiment when the lug rides off the cam 36 the force stored in the spring 31 will swing the lever 29 in order to bring about the operations referred to above. However, with the embodiment of FIG. 3 the projection 40 strikes against the arm 64 of the releasable pawl means so as to swing the pawl 60 in opposition to the spring 61 in a counterclockwise direction, as viewed in FIG. 3, through an angle sufficient to displace the tooth 62 beyond the tooth 63, and now the spring 20 can continue the upward movement of the plunger 5 to its ignition position where it acts on the ignition spring 8 in order to bring about ignition of the lamp.

As a result of the fact that the relay or ignition spring 8 of a flash lamp of the flashcube is located so that the plunger 5 can have access thereto only through a relatively deep opening, it is essential for the plunger 5 to move through a relatively long distance before it can bring about ignition of a lamp. With the non-linear transmission means of the invention a relatively small initial increment of movement of the shutter-release means brings about the required relatively long preliminary movement of the ignition plunger 5. However, after this initial rapid movement of the ignition plunger the transmission ratio of the non-linear transmission means changes so that during the remaining greater part of the movement of the shutter-release means all or at least the greatest part of the energy required for igniting the flash lamp is obtained.

Also with the invention there is the advantage that when an ignited flash lamp is in an exposure position the ignition spring 8 is no longer in a position to resist the upward movement of the plunger 5 so that the lastmotion transmission does not operate and the stop means 43 becomes effective to prevent movement of the shutter-release means all the way to the shutterrelease position so that in this way tripping of the shutter is avoided under these conditions.

It is apparent, therefore, that as a result of the nonlinear transmission means of the invention, in the form of a pin-and-slot connection in the illustrated example, the additional energy required from the shutter release in order to ignite the flash lamp is provided in an advantageous manner by distributing the storage of the required force throughout the entire movement of the shutter-release means. The initial part of this move ment provides for the free movement of the ignition plunger with an extremely small increment of initial movement of the shutter-release means almost up to the ignition position and then the greatest part of the movement of the shutter-release means is utilized to store the actuating energy required for the final increment of movement of the ignition plunger. A further highly important advantage of the invention resides in the reliable prevention of erroneous attempts to make an exposure with a previously ignited flash lamp.

The structure of the invention which achieves the above advantages and objects of the invention is relatively simple and inexpensive and can easily be manufactured in a highly advantageous manner to convert existing camera mechanisms so that they can readily function with mechanically ignitable flash lamps of flashcubes.

What is claimed is:

l. In a camera for making exposures with a flashcube having a plurality of flash lamps adapted to be moved successively into an ignition position in response to film transport and adapted to be mechanically ignited, an elongated ignition plunger for mechanically igniting a flash lamp of a flashcube when the flash lamp is in the ignition position, guide means coacting with said plunger for guiding the latter for longitudinal movement from a rest position to an ignition position, manually-operable shutter-release means for tripping a shutter of the camera to make an exposure, and nonlinear transmission means coacting with said shutterrelease means and said plunger for transmitting movement of said shutter-release means to said plunger for moving the latter in response to actuation of said shutter-release means from said rest position toward said ignition position at a relatively fast rate during an initial part of the movement of said shutter-release means and at a relatively slow rate during a final part of the movement of said shutter-release means so that said plunger is moved through most of the distance from said rest toward said ignition position during the initial part of the movement of said shutter-release means.

2. The combination of claim 1 and wherein said nonlinear transmission means includes a lost-motion transmission having an input member driven by said shutterrelease means, an output member freely movable with respect to said input member andoperatively connected to said plunger to transmit the drive thereto, and a transmission spring coacting with said input and output members for urging said output member to move with said input member.

3. The combination of claim 2 and wherein said transmission spring is strong enough to move said plunger almost up to its ignition position but is too weak to displace said plunger with the force required to move the latter to effect ignition of a lamp, so that when said plunger has almost reached said ignition position said transmission spring no longer moves said output member together with said input member and the latter continues to be moved by said shutter-release means while said output member remains stationary and said transmission spring yields.

4. The combination of claim 3 and wherein said shutter-release means includes a shutter-tripping member which trips the camera shutter to make an exposure after said output member has stopped moving and while said input member continues to move during yielding of said transmission spring, said shuttertripping member when acting to trip the shutter also coacting with said output member for supplementing the force of said transmission spring to an extent sufficient to'move said output member through an increment great enough to displace said plunger to said ignition position so as to bring about ignition of a flash lamp in synchronism with the opening of the shutter.

5. The combination of claim 4 and wherein said transmission spring moves said output member sufficiently to displace said plunger all the way to said ignition position thereof when said plunger encounters a previously ignited lamp which thus does not resist movement of said plunger by said transmission spring, and stop means operatively connected with said output member to be actuated thereby for stopping operation of said shutter-release means before the' shutter is tripped when said transmission spring moves said plunger through said output member all the way to said ignition position while the termination in the movement of said output member when said plunger encounters a lamp which is to be ignited prevents said stop means from interrupting the operation of said shutter-release means.

6. The combination of claim 5 and wherein a sensing means senses the presence or absence of a flashcube by assuming difierent positions depending upon the presence or absence of a flashcube, said sensing means when in said position corresponding to absence of a flashcube being situated in the path of movement of said stop means for preventing the latter from interfering with the operation of said shutter-release means.

7. The combination of claim 2 and wherein said transmission spring is strong enough to move said output member sufficiently to displace said plunger to said ignition position thereof.

8. The combination of claim 7 and wherein a releasable pawl means coacts with said plunger for preventing the latter from being moved by said transmission spring and output member to said ignition position.

9. The combination of claim 8 and wherein said shutter-release means includes a shutter-tripping member which trips the shutter to make the exposure at the end of the movement of said shutter-release means, said shutter-tripping member coacting with said pawl means for releasing the action of the latter on said plunger so as to release the latter to said transmission spring in synchronism with the tripping of the shutter.

10. The combination of claim 1 and wherein a flashcube socket is formed with a plurality of openings which successively become located in the path of movement of said plunger as the lamps of the flashcube are successively moved to the exposure position so that for each lamp of a flashcube said socket has an opening through which the plunger moves. 

1. In a camera for making exposures with a flashcube having a plurality of flash lamps adapted to be moved successively into an ignition position in response to film transport and adapted to be mechanically ignited, an elongated ignition plunger for mechanically igniting a flash lamp of a flashcube when the flash lamp is in the ignition position, guide means coacting with said plunger for guiding the latter for longitudinal movement from a rest position to an ignition position, manually-operable shutterrelease means for tripping a shutter of the camera to make an exposure, and non-linear transmission means coacting with said shutter-release means and said plunger for transmitting movement of said shutter-release means to said plunger for moving the latter in response to actuation of said shutter-release means from said rest position toward said ignition position at a relatively fast rate during an initial part of the movement of said shutter-release means and at a relatively slow rate during a final part of the movement of said shutter-release means so that said plunger is moved through most of the distance from said rest toward said ignition position during the initial part of the movement of said shutter-release means.
 2. The combination of claim 1 and wherein said non-linear transmission means includes a lost-motion transmission having an input member driven by said shutter-release means, an output member freely movable with respect to said input member and operatively connected to said plunger to transmit the drive thereto, and a transmission spring coacting with said input and output members for urging said output member to move with said input member.
 3. The combination of claim 2 and wherein said transmission spring is strong enough to move said plunger almost up to its ignition position but is too weak to displace said plunger with the force required to move the latter to effect ignition of a lamp, so that when said plunger has almost reached said ignition position said transmission spring no longer moves said output member together with said input member and the latter continues to be moved by said shutter-release means while said output member remains stationary and said transmission spring yields.
 4. The combination of claim 3 and wherein said shutter-release means includes a shutter-tripping member which trips the camera shutter to make an exposure after said output member has stopped moving and while said input member continues to move during yielding of said transmission spring, said shutter-tripping member when acting to trip the shutter also coacting with said output member for supplementing the force of said transmission spring to an extent sufficient to move said output member through an increment great enough to displace said plunger to said ignition position so as to bring about ignition of a flash lamp in synchronism with the opening of the shutter.
 5. The combination of claim 4 and wherein said transmission spring moves said output member sufficiently to displace said plunger all the way to said ignition position thereof when said plunger encounters a previously ignited lamp which thus does not resist movement of said plunger by said transmission spring, and stop means operatively connected with said output member to be actuated thereby for stopping operation of said shutter-release means before the shutter is tripped when said transmission spring moves said plunger through said output member all the way to said ignition position while the termination in the movement of said output member when said plunger encounters a lamp which is to be ignited prevents said stop means from interrupting the operation of said shutter-release means.
 6. The combination of claim 5 and wherein a sensing means senses the presence or absence of a flashcube by assuming different positions depending upon the presence or absence of a flashcube, said sensing means when in said position corresponding to absence of a flashcube being situated in the path of movement of said stop means for preventing the latter from interfering with the operation of said shutter-release means.
 7. The combination of claim 2 and wherein said transmission spring is strong enough to move said output member sufficiently to displace said plunger to said ignition position thereof.
 8. The combination of claim 7 and wherein a releasable pawl means coacts with said plunger for preventing the latter from being moved by said transmission spring and output member to said ignition position.
 9. The combination of claim 8 and wherein said shutter-release means includes a shutter-tripping member which trips the shutter to make the exposure at the end of the movement of said shutter-release means, said shutter-tripping member coacting with said pawl means for releasing the action of the latter on said plunger so as to release the latter to said transmission spring in synchronism with the tripping of the shutter.
 10. The combination of claim 1 and wherein a flashcube socket is formed with a plurality of openings which successively become located in the path of movement of said plunger as the lamps of the flashcube are successively moved to the exposure position so that for each lamp of a flashcube said socket has an opening through which the plunger moves. 